Directions and Blood Relations
Overview
Directions and Blood Relations form a core component of the Reasoning section in HTET across all three levels (PRT, TGT, PGT). These topics test your ability to visualise spatial orientation and decode family relationships—skills that reflect logical thinking capacity expected of teachers.
Mastery here offers quick, reliable marks since the underlying logic is finite and learnable. Unlike arithmetic, these problems reward methodical diagramming over calculation speed.
Students must internalise the eight-point compass, shadow-based direction inference, and a systematic approach to family trees. Once the mental framework is solid, even complex multi-step problems become mechanical.
Key Concepts
Direction Sense:
- The compass has 8 standard directions: North (N), South (S), East (E), West (W), and four intermediates—North-East (NE), North-West (NW), South-East (SE), South-West (SW).
- A person turning "right" rotates clockwise; turning "left" rotates anti-clockwise.
- At sunrise, your shadow falls towards the West; at sunset, it falls towards the East. At noon, the shadow is shortest and points North (in India, which lies north of the equator).
- Displacement and direction are different: total distance walked is not the same as straight-line distance from start to end.
Blood Relations:
- Every relation can be traced through three basic links: parent-child, spouse, and sibling.
- Gender indicators include words like son, daughter, brother, sister, husband, wife, uncle, aunt, nephew, niece.
- "Only son/daughter" or "no siblings" are critical constraints—they eliminate extra family members.
- Coded blood relations substitute symbols (e.g., A + B means A is father of B) and require decoding before solving.
Formulas / Key Facts
| Fact | Explanation |
|---|---|
| Right turn = +90° clockwise | From North → East → South → West → North |
| Left turn = +90° anti-clockwise | From North → West → South → East → North |
| Opposite directions | N↔S, E↔W, NE↔SW, NW↔SE |
| Shadow at sunrise | Falls to the West (sun in East) |
| Shadow at sunset | Falls to the East (sun in West) |
| Father's or Mother's son | Brother (or self if "only son") |
| Father's or Mother's daughter | Sister (or self if "only daughter") |
| Brother's/Sister's son | Nephew |
| Brother's/Sister's daughter | Niece |
| Father's brother | Uncle (Chacha/Tau) |
| Mother's brother | Maternal uncle (Mama) |
| Son's wife | Daughter-in-law (Bahu) |
| Daughter's husband | Son-in-law (Damaad) |
Worked Examples
Example 1: Direction Sense (Basic)
Problem: Ramesh walks 5 km North, then turns right and walks 3 km, then turns right again and walks 5 km. In which direction is he from his starting point?
Solution:
- Start at origin O facing North.
- Walk 5 km North → reaches point A.
- Turn right (now facing East), walk 3 km → reaches point B.
- Turn right (now facing South), walk 5 km → reaches point C.
Draw it:
- North 5 km cancels with South 5 km (vertical displacement = 0).
- Net movement = 3 km East.
Answer: Ramesh is to the East of his starting point.
Example 2: Shadow-Based Direction
Problem: One morning, Sita was walking. The sun was behind her and her shadow fell to her right. Which direction was she facing?
Solution:
- Morning → Sun in East → Shadow falls West.
- Shadow to her right means West is on her right.
- If West is to the right, she is facing South.
Answer: South
Example 3: Blood Relation
Problem: Pointing to a photograph, Anil said, "He is the son of my mother's only daughter." How is the person in the photograph related to Anil?
Solution:
- Anil's mother's only daughter = Anil's sister (if Anil is male, his mother's only daughter is his sister; if Anil were female, it would be Anil herself, but "He" indicates a male in the photo).
- Son of Anil's sister = Anil's nephew.
Answer: Nephew
Example 4: Coded Blood Relation
Problem: If A + B means A is the father of B, A – B means A is the wife of B, and A × B means A is the brother of B, then what does P + Q – R mean?
Solution:
- P + Q → P is father of Q.
- Q – R → Q is wife of R.
So P is father of Q, and Q is married to R. This means P is the father-in-law of R.
Answer: P is the father-in-law of R.
Common Mistakes
| Wrong Thinking | Correct Fix |
|---|---|
| Confusing "right turn" with "move right" | A right turn changes your facing direction by 90° clockwise; it doesn't mean stepping sideways. |
| Assuming shadow direction without checking time of day | Always verify: sunrise = shadow West, sunset = shadow East, noon = shadow North (in Northern Hemisphere). |
| Forgetting "only" constraints | "My mother's only son" is the speaker himself if male, not a brother. Read constraints carefully. |
| Mixing up in-laws with blood relatives | Son-in-law and daughter-in-law are related by marriage, not by blood. Trace through the spouse link. |
| Not drawing diagrams | Attempting to solve directions or complex family trees mentally leads to errors. Always sketch. |
Quick Reference
- Right = Clockwise, Left = Anti-clockwise — visualise yourself standing at the centre of a compass.
- Sunrise shadow West, Sunset shadow East — memorise as "Sun-Shadow opposite."
- Draw family trees top-down — place older generations above, use = for spouse, vertical lines for children.
- "Only son/daughter" often means self — critical for tricky questions.
- Opposite direction pairs: N↔S, E↔W, NE↔SW, NW↔SE — instant elimination in MCQs.
- Decode symbols first in coded relations — rewrite the expression in plain relation words before solving.